By Tompion's death, in 1713, dailyvariation was less than a minute, and by the late 19th century, marine chronometers were accurate to fractions of a second per day.
The National Statistics figures also showed there was a dailyvariation, something which has been seen since the 1970s, with more children born on weekdays compared to weekends and bank holidays.
Third, the child with bipolar disorder often has a dailyvariation: he becomes highly active at night and in the morning he is like a hibernating bear, all but impossible to get out of bed.